diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 28 | ||||
| -rw-r--r-- | kernel/irq/irqdomain.c | 12 | ||||
| -rw-r--r-- | kernel/mutex.c | 1 |
3 files changed, 26 insertions, 15 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1833bc5a84a7..eba8fb5834ae 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -947,8 +947,18 @@ perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) { struct perf_event_context *ctx; - rcu_read_lock(); retry: + /* + * One of the few rules of preemptible RCU is that one cannot do + * rcu_read_unlock() while holding a scheduler (or nested) lock when + * part of the read side critical section was preemptible -- see + * rcu_read_unlock_special(). + * + * Since ctx->lock nests under rq->lock we must ensure the entire read + * side critical section is non-preemptible. + */ + preempt_disable(); + rcu_read_lock(); ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); if (ctx) { /* @@ -964,6 +974,8 @@ retry: raw_spin_lock_irqsave(&ctx->lock, *flags); if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { raw_spin_unlock_irqrestore(&ctx->lock, *flags); + rcu_read_unlock(); + preempt_enable(); goto retry; } @@ -973,6 +985,7 @@ retry: } } rcu_read_unlock(); + preempt_enable(); return ctx; } @@ -1950,7 +1963,16 @@ static int __perf_event_enable(void *info) struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); int err; - if (WARN_ON_ONCE(!ctx->is_active)) + /* + * There's a time window between 'ctx->is_active' check + * in perf_event_enable function and this place having: + * - IRQs on + * - ctx->lock unlocked + * + * where the task could be killed and 'ctx' deactivated + * by perf_event_exit_task. + */ + if (!ctx->is_active) return -EINVAL; raw_spin_lock(&ctx->lock); @@ -7465,7 +7487,7 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent, * child. */ - child_ctx = alloc_perf_context(event->pmu, child); + child_ctx = alloc_perf_context(parent_ctx->pmu, child); if (!child_ctx) return -ENOMEM; diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 2d7cd3428365..706724e9835d 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -475,18 +475,6 @@ unsigned int irq_create_of_mapping(struct device_node *controller, domain = controller ? irq_find_host(controller) : irq_default_domain; if (!domain) { -#ifdef CONFIG_MIPS - /* - * Workaround to avoid breaking interrupt controller drivers - * that don't yet register an irq_domain. This is temporary - * code. ~~~gcl, Feb 24, 2012 - * - * Scheduled for removal in Linux v3.6. That should be enough - * time. - */ - if (intsize > 0) - return intspec[0]; -#endif pr_warn("no irq domain found for %s !\n", of_node_full_name(controller)); return 0; diff --git a/kernel/mutex.c b/kernel/mutex.c index e581ada5faf4..ff05f4bd86eb 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -18,6 +18,7 @@ * Also see Documentation/mutex-design.txt. */ #include <linux/mutex.h> +#include <linux/ww_mutex.h> #include <linux/sched.h> #include <linux/sched/rt.h> #include <linux/export.h> |